A 1000 MW fission reactor consumes half of its fuel in 5.00 y. How much 23592U did it contain initially? Assume that the reactor operates 80% of the time, that all the energy generated arises from the fission of 23592U and that this nuclide is consumed only by the fission process.

Half-life of the fuel in the fission reactor = 5 years

= 5 × 365 × 86400 s ( 1 day = 86400 seconds)


= 1.576 × 108 sec


1 gm of Uranium fission gives 200 MeV energy [This can be worked out from the fission equation given below of Uranium].



1 gm of Uranium, =


Energy generated by Uranium fission =


= J


= 8.2 × 1010 J/gm


The 1000MW reactor operates only 80% of it’s time,hence in 5 years amount of uranium consumed


=


= 1538 kg


This amount is consumed within the half life time.


Hence, the initial amount will be = 2 × 1538Kg


= 3076Kg


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